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On spacewalk, crew attaches truss to station

Atlantis' mission is extended to repair a torn thermal blanket.

The crew of the space shuttle Atlantis successfully attached a 35,000-pound truss to the International Space Station on Monday, preparing the way for Japanese and European science labs that will be added next year.

As the spacewalk was winding up, NASA officials decided to extend the mission for two days so the astronauts could repair a torn thermal blanket on the shuttle's exterior.

The truss carries solar panels that will add 14 kilowatts of energy-generating capacity to the station, doubling its capacity.

The crew used Atlantis' robotic arm to lift the truss from the shuttle's cargo bay and attach it to the station.

Astronauts Jim Reilly and John "Danny" Olivas then donned spacesuits and exited the shuttle to perform the nuts-and-bolts operations of the mission, making power, data and cooling connections between the truss and the station.

The spacewalk was delayed for more than an hour when the station's four gyroscopes that keep it properly oriented were overloaded. Control jets on the shuttle were used to help the station maintain equilibrium until the gyroscope could take over again.

On the 6.5-hour mission, Reilly and Olivas also released locks and launch restraints on the solar panels, preparing them to be deployed later in the week.

During the spacewalk, the astronauts followed new procedures to ensure that they did not lose any bolts or tools. In September, several bolts accidentally entered orbit when astronauts performed a similar spacewalk to install a truss.

The astronauts also inspected their gloves after each procedure to ensure that no cuts or rips had occurred, a new requirement for this mission.

A 4-by-6-inch section of the thermal blanket covering Atlantis' engine pods was apparently torn free by air pressure during the shuttle's launch Friday evening.

Engineers do not fear for the shuttle's safety on reentry because that area of the craft undergoes much lower temperatures than the nose and wings.

Structures under the blanket are composed of carbon fiber, which is also resistant to heat.

But John Shannon, chairman of the mission management team, said in a news conference Monday evening that NASA didn't want to risk damaging the engines, necessitating repairs that could delay the agency's three remaining launches this year.

"I don't want to take the risk of damaging my flight hardware," he said.

The management team has scheduled a fourth spacewalk for the mission on Sunday, but Shannon said it had not yet decided whether the repairs would be attempted on that spacewalk or the third one.

Astronauts could either trim off the loosened section of the blanket, tuck it back into place under the protective tiles or glue a heat-resistant plate over it.

The shuttle has carried a tile and blanket repair kit since the 2003 Columbia disaster, in which the shuttle broke up during reentry.

With two days added to the mission, Atlantis is scheduled to return to the Kennedy Space Center in Florida on June 21.